Synthesis and Diels−Alder Reactions of 4-Substituted- 1,3-diphenoxy-2-[(tert-butyldimethylsilyl)oxy]-1,3-butadienes: Application to the Synthesis of Triaryl Ethers
摘要:
A novel class of tetrahetero-substituted 1,3-dienes 1a-d having aryl ether substituents at the 1,3-positions were synthesized by enol silylation of 4-substituted 1,3-diphenoxy-3-buten-2-ones-3a-c. The 1Z,3Z configuration of 1b has been assigned by X-ray crystallography. The synthesis of triaryl ethers utilizing a Diels-Alder approach involved reaction of diene la with methyl acrylate to furnish a 3:1 mixture of endo- and exo-adducts. Conversion of the adducts to cyclohexenone 8 and aromatization with DDQ gave triaryl ether 9. Cycloaddition reactions of la, Ib with some conjugated alkenes exhibited excellent regiospecificity and endo stereoselectivity.
Synthesis and Diels−Alder Reactions of 4-Substituted- 1,3-diphenoxy-2-[(tert-butyldimethylsilyl)oxy]-1,3-butadienes: Application to the Synthesis of Triaryl Ethers
摘要:
A novel class of tetrahetero-substituted 1,3-dienes 1a-d having aryl ether substituents at the 1,3-positions were synthesized by enol silylation of 4-substituted 1,3-diphenoxy-3-buten-2-ones-3a-c. The 1Z,3Z configuration of 1b has been assigned by X-ray crystallography. The synthesis of triaryl ethers utilizing a Diels-Alder approach involved reaction of diene la with methyl acrylate to furnish a 3:1 mixture of endo- and exo-adducts. Conversion of the adducts to cyclohexenone 8 and aromatization with DDQ gave triaryl ether 9. Cycloaddition reactions of la, Ib with some conjugated alkenes exhibited excellent regiospecificity and endo stereoselectivity.